Erru, the Great Phoenix

A while back I took the text of one of the cantrips I had created, and built a creature and a lair around the information provided therein. It was a fun little project and I think the results were pretty interesting. It’s hard to judge the efficacy of the encounter design, being that it’s meant to be a campaign topper, and given the fact the Rakshasa is a weird creature to begin with. Being flat out immune to 6th-level spells and below does some bizarre things, ya know? Anyway, I liked doing it enough that I wanted to do it some more, again building off the cantrips I wrote. This time around, I am taking the text of the wildfire cantrip, and looking at Erru, the Great Phoenix.

Flash Fire

It is implied in the text for wildfire that Erru, the Great Phoenix is an impartial guardian figure in a nation that venerates a fire-centric pantheon. The Charred King and the Queen of Ashes are mentioned in the text as figures that live beyond a bridge in the fields of flame. It’s (hopefully) clear from the text the king and queen are deific figures, and that Erru is a dangerous, uncaring guardian to their realm. Erru obviously means a great deal to the people, appearing as the symbol of their nature and on their currency, but people do not worship it. Instead, they fear and respect Erru, hoping to never need to encounter it or meet its gaze.

Erru is meant to be a towering figure of legend, but one that is able to be overcome by stalwart adventurers. Instead of being an end of campaign figure, Erru is meant to be more of a beginning of a great high-level adventure encounter, starting off the pursuit of a goal on an epic note (again, hopefully).

The Royal Bridge

Within the elemental plane of fire resides the domain of the Charred King and the Queen of Ashes. Entrance to the fiery fields of their demesne is only possible by traversing the Royal Bridge. The bridge is made from polished onyx bricks made from the prayers of the devout, and mortared by the burnt offerings sacrificed to the King and Queen. The bridge spans the Flameblight River, the magic of the bridge shielding those crossing the bridge from the terrible spreading heat of the river below. The bridge is without rails or guides, so that the sweeping winds that blow across the river can send trespassers off the bridge and to their fiery demise.

Adventurers might find need to cross the bridge to petition the Charred King and the Queen of Ashes for a favor during Bonfire Night. They might also seek to gain their blessing to travel into the Ice Caverns of Olith to confront Grand Duchess Olith. Other simply attempt the feat to claim a sacrificed treasure from the Royal Vault. Whatever the reason, the adventurers must first pass the Royal Bridge, and endure the song of Erru, the Great Phoenix.

Lair Actions

When fighting in its lair, Erru can invoke the magic of the Royal Bridge to take lair actions. On initiative count 20 (losing initiative ties), Erru takes a lair action to cause one of the following effects:

Erru, the Great Phoenix can temporarily lower the magic around the bridge, allowing searing winds to sweep across it. Any creature on the bridge must make a DC 18 Strength saving throw or be pushed 30 feet and knocked prone. If the creature is pushed off the edge, the creature must succeed on a DC 18 Strength (Athletics) or Dexterity (Acrobatics) check or fall into the Flameblight River. Erru, the Great Phoenix may not use this lair action again until it has used a different one.

The burnt offerings to the king and queen rise up from the mortar of the bridge. The area becomes difficult terrain from the accumulating ash, and the bridge becomes bathed in magical darkness. While maintaining concentration on this effect, Erru, the Great Phoenix can’t take other lair actions.

A tendril of fire from the Flamebright river lashes at trespassers on the bridge. Any creature within 30 feet of an edge must make a DC 18 Dexterity saving throw or take 14 (4d6) fire damage. Erru, the Great Phoenix can’t use this lair action again until it has used a different one.

Regional Effects

The Royal Bridge is the entryway to the domain of the king and queen, and those who cross it are entering into a domain of fire and flame. This alters the surrounding environs in the following ways:

The air is increasingly difficult to breathe, wearing down the endurance of travelers. All exhaustion checks are made with disadvantage.

Cold is not as effective as it would otherwise be, and liquid boils very quickly. All liquids boil within one hour of approaching the bridge, if they are able to do so. All cold damage is reduced by 1d6, prior to any saving throw reduction or resistance.

As an action, Erru, the Great Phoenix can appear as an illusory image within 3 miles of the bridge. Once creature, the image lasts for as long as Erru, the Great Phoenix maintains concentration, as if concentrating on a spell. Although the image is intangible, it looks, sounds, and can move like Erru, the Great Phoenix. Erru, the Great Phoenix can sense, speak, and use telepathy from the image’s position as if present at that position. If the image takes any damage, it disappears.

Design Notes

This is designed as the first really difficult encounter for a group approaching high-level game play. Erru has a pile of immunities, mostly conditions due to its status as an eternal guardian. Its theme is meant to convey an ever-present vigilance, thus the possess of truesight, as well. Other than that, Erru is immune to fire to stay in theme with fire elementals in this edition (your mileage may vary, of course), and poison just to communicate purity. I should probably have it be immune to disease, too, but it’s so rare in PC hands as to be a negligible afterthought. What I mean is, I forgot, obviously. Anyway, beyond that is a defense again non-magical weapons, but at 13th-16th level, they are probably not too worried about that, unless you set out to make them worry.

Erru is based largely on the Roc, and pulling from the Ice Devil and Dragon for ways to incorporate some higher CR abilities and how to handle a variety of abilities and actions. I wanted the dive bomb/rise for the ashes feel of Blaze of Glory to allow a brief respite for the players in the midst of the encounter. A round to heal/change tactics can be crucial for a fight, and for something as on-paper difficult as this, I think that cuts down on the difficulty to some degree.

As with all things in 5e, even with following guidelines, CR prediction can be a hard thing, particularly once you start in with legendary actions and lairs. I think this feels right, but it’s hard to know for sure.